This invention relates to a method for modifying metallic paint coated on a surface by inducing a color shift in the paint in a desired area and to the product so-produced.
At the present time, metallic paints are used extensively, particularly in the automotive industry, to produce a dress coat because they exhibit a shininess and color flop when viewed at different angles. These characteristics of metallic paint give the final paint finish a dimensional or contoured appearance. It is common practice, particularly in the automotive industry, to create a two tone effect or form trim stripes which are painted separately on the surface utilizing a masking technique. These processes are labor intensive and require considerable skill to insure obtaining the same finish as the dress coat when the different colored paint is applied.
It would be highly desirable to provide a means for producing a two tone or trim effect on a surface painted with metallic paint without the need for applying separate paint coats to the surface. Furthermore, it would be desirable to provide such a means which permits modifying the metallic paint precisely in a desired design to produce a two tone effect.
In accordance with this invention, a method is provided for subjecting an electrically conductive substrate coated with a metallic paint to a small corona current in order to orient the metallic particles in the paint in the direction of the corona current. By orienting the flat metallic particles in the paint in the same direction, a color contrast to the originally applied paint is produced in the treated portion of the paint. The metallic paint is subjected to the corona current while the paint is still wet and therefore while the metallic particles in the paint are still mobile under the influence of the electrical field caused by the corona current. The present invention also provides the product produced by the process of this invention comprising the electrically conductive substrate coated with a metallic paint wherein at least a portion of the coated metallic paint includes an area wherein the metallic particles are oriented in essentially the direction vertical to the substrate surface.